Medical systems and methods

ABSTRACT

This disclosure generally relates to medical systems and methods. In one aspect of the invention, a method includes determining a fluorescent light intensity at one or more points on each of multiple recorded images, and producing an image based on the determined fluorescent light intensity at the one or more points.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority under 35 USC120 to, U.S. application Ser. No. 12/331,874, filed Dec. 10, 2008, whichclaims the benefit of U.S. application Ser. No. 61/191,748, filed onSep. 11, 2008. The contents of both of these applications are herebyincorporated by reference in its entirety.

TECHNICAL FIELD

This disclosure relates to medical systems and methods.

BACKGROUND

Neuro-surgical therapy is a technique that can be used to treat ananeurysm, i.e., a sac shaped localized enlargement of the cross-sectionof a patient's artery. During neuro-surgical therapy, a clip istypically used to clamp off the aneurysm from the blood circulation.Neuro-surgical therapy can decrease the likelihood of the aneurysmrupturing.

To determine whether the aneurysm sac has been completely closed withthe clip and whether the blood flows properly in other arterial vesselsin close proximity to the clip, a fluorescent dye can be administeredintravenously to the patient and the flow of the dye into the artery canbe observed through a camera. If the blood mixed with the fluorescentdye is visible in the aneurysm sac, this indicates that the aneurysm sacwas not completely closed with the clip. Similarly, if the blood mixedwith the fluorescent dye is not visible in certain regions of the arteryuntil after a delay, this can indicate that those regions of the arteryare least partially blocked.

SUMMARY

In one aspect of the invention, a method includes determining afluorescent light intensity at one or more points on each of multipleimages of tissue of a subject and producing an image based on thedetermined fluorescent light intensity at the one or more points.

In another aspect of the invention, a method includes recording multipleimages of a region of a blood vessel, analyzing the multiple recordedimages to determine a maximum fluorescent light intensity at multiplepoints on each of the recorded images, and displaying an image thatrepresents the maximum fluorescent light intensity at each of themultiple points.

In an additional aspect of the invention, a method includes recordingmultiple images of a region of a blood vessel, analyzing the multipleimages to determine a time at which a predetermined fluorescent lightintensity was reached for each of multiple points on each of therecorded images, and displaying an image that represents a relativeamount of time for each point to reach the predetermined fluorescentlight intensity.

In a further aspect of the invention, a method includes recordingmultiple images of a region of a blood vessel, analyzing the multiplerecorded images to determine a fluorescent light intensity at each ofmultiple points on each of the recorded images, and displaying an imagethat represents the fluorescent light intensity for each of the multiplepoints over a period of time.

In another aspect of the invention, a method of treating an aneurysmincludes: exposing an aneurysm at a surgical site; injecting afluorescent dye into a blood vessel that includes the aneurysm;capturing a first set of images of the surgical site with a camera;analyzing the first set of images captured by the camera in a signalprocessing and analysis unit; applying a clip to the aneurysm to clampoff the aneurysm; after applying the clip to the aneurysm, capturing asecond set of images of the surgical site with the camera; analyzing thesecond set of images captured by the camera in a signal processing andanalysis unit; and comparing the first set of images with the second setof images to determine the effectiveness of the clip to clamp of theaneurysm.

In an additional aspect of the invention, a system includes a computersystem with a processor for executing instructions and memory storing acomputer program product which, when executed by the processor, performsa method that includes determining a fluorescent light intensity at oneor more points on each of multiple images of tissue of a subject andproducing an image based on the determined fluorescent light intensityat the one or more points.

In a further aspect of the invention, a system includes a computerprogram product capable of determining a fluorescent light intensity atone or more points on each of multiple images of tissue of a subject andproducing an image based on the determined fluorescent light intensityat the one or more points.

Embodiments can include one or more of the following features.

In some embodiments, the method further includes recording the multipleimages of the tissue of the subject.

In certain embodiments, determining the fluorescent light intensity atthe one or more points on each of the multiple images involves analyzingeach of the multiple images.

In some embodiments, the method further includes displaying the imagebased on the determined fluorescent light intensity at the one or morepoints.

In certain embodiments, determining the fluorescent light intensity atthe one or more points on each of the multiple images involvesdetermining a maximum fluorescent light intensity at the one or morepoints on each of the multiple images.

In some embodiments, the image that is produced based on the determinedfluorescent intensity at the one or more points is a representation ofthe maximum fluorescent intensity determined at the one or more points.

In certain embodiments, the one or more points on each of the multipleimages includes multiple points on each of the multiple images.

In some embodiments, the maximum fluorescent light intensity at each ofthe multiple points is represented by a brightness, and the brightnessincreases as the maximum fluorescent light intensity increases.

In certain embodiments, the method further includes determining a timeat which a predetermined fluorescent light intensity was reached at eachof the one or more points.

In some embodiments, the image that is produced based on the determinedfluorescent intensity at the one or more points represents an amount oftime for each of the one or more points to reach the predeterminedfluorescent light intensity after introducing a fluorescent substanceinto the tissue of the subject.

In certain embodiments, the amount of time required for each of the oneor more points to reach the predetermined fluorescent light intensityafter introducing the fluorescent substance into the tissue of thesubject is represented by a color on the produced image.

In some embodiments, the one or more points on each of the multipleimages includes multiple points on each of the multiple images.

In certain embodiments, the greatest amount of time required to reachthe predetermined fluorescent light intensity among the multiple pointsis represented as a first color, and the least amount of time requiredto reach the predetermined fluorescent light intensity among themultiple points is represented as a second color that is different thanthe first color.

In some embodiments, times to reach the predetermined fluorescent lightintensity that are between the greatest amount of time and the leastamount of time are represented by a combination of the first and secondcolors.

In certain embodiments, the image that is produced based on thedetermined fluorescent intensity at the one or more points includes agraph illustrating the determined fluorescent intensity at the one ormore points over a period of time.

In some embodiments, the one or more points on each of the multipleimages comprises multiple points on each of the multiple images.

In certain embodiments, the multiple images of the tissue of the subjectare recorded by a camera.

In some embodiments, the multiple images of the tissue of the subjectare analyzed by a microprocessor connected to the camera.

In certain embodiments, the image based on the determined fluorescentlight intensity at the one or more points is displayed by a screenconnected to the microprocessor.

In some embodiments, the tissue of the subject includes a blood vesselof the subject.

In certain embodiments, the method further includes introducing afluorescent substance into the blood vessel.

In some embodiments, the method further includes applying light having awavelength of 400 nm to780 nm to the blood vessel.

In certain embodiments, the multiple images are recorded with afluorescent light camera.

In some embodiments, the multiple images are analyzed by a processor.

In certain embodiments, the method further includes transmitting themultiple images from a camera to the processor.

In some embodiments, the multiple points on each of the multiple imagesincludes all of the points on each of the multiple images.

In certain embodiments, the method further includes treating the tissueof the subject.

In some embodiments, the multiple images are images of the tissue of thesubject before the tissue of the subject is treated.

In certain embodiments, the method further includes determining afluorescent light intensity at one or more points on each of a secondmultiple images of the tissue of the subject after treatment of thetissue of the subject, and producing an image based on the determinedfluorescent light intensity at the one or more points.

In some embodiments, the method further includes simultaneouslydisplaying the produced images.

In certain embodiments, the method further includes comparing theproduced images to assess the success of the treatment.

In some embodiments, the method further includes adjusting the images ofthe multiple images so that corresponding points on each of the imagesare aligned with one another.

In certain embodiments, the imaged region includes multiple bloodvessels.

In some embodiments, the system further includes a camera adapted torecord the multiple images of the tissue of the subject.

In certain embodiments, the system further includes a display adapted todisplay the image based on the fluorescent intensity at the one or morepoints.

In some embodiments, the processor is adapted to transmit to the displaya signal containing the image based on the fluorescent intensity at theone or more points.

In certain embodiments, the processor is adapted to adjust the series ofimages so that corresponding points on each of the images are alignedwith one another.

In some embodiments, the system further includes a fluorescent lightsource that can be arranged to direct fluorescent light to the site.

In certain embodiments, the system is an operating microscope.

In some embodiments, the computer program product is software.

Embodiments can include one or more of the following advantages.

In some embodiments, the methods enable a physician to check the stateof blood flow through a blood vessel by viewing a single image. Ascompared to certain previous methods that required the physician to viewa series of images to determine certain patterns of blood flow (e.g.,the amount of blood flow through certain regions of the blood vessel,the amount of time required for blood flow to reach certain regions ofthe blood vessel, etc.), methods described herein can decrease theamount of time that it takes to determine these blood flow patterns.

In certain embodiments, the methods allow the physician to view bloodflow patterns at discrete points within a blood vessel. This can providethe physician with detailed information about a specific region of ablood vessel (e.g., an aneurysm in the blood vessel). This can improvethe ability of the physician to make treatment decisions or assess thesuccess of a treatment.

In some embodiments, the systems and methods permit the physician tosimultaneously view an image showing pre-treatment blood flow patternsand an image showing post-treatment blood flow patterns on a singledisplay screen. As a result, the physician can more quickly assess thesuccess of the treatment.

In certain embodiments, blood flow patterns are displayed as abrightness gradient or color gradient, which allows the user to quicklyassess the state of blood flow. In some embodiments, for example, theuser can simply determine whether a certain region of a displayed bloodvessel is bright v. dark or red v. blue to assess the state of bloodflow in that region. As a result, the speed and efficiency with whichthe assessment is performed can be increased.

Other aspects, features, and advantages will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic of an operating microscope system.

FIG. 2 is an image of a blood vessel with an aneurysm, as viewed throughthe operating microscope of FIG. 1.

FIG. 3 illustrates a display screen of the operating microscope of FIG.1, displaying a spatial distribution of the maximum intensity offluorescence light in the blood vessel region shown in FIG. 2.

FIG. 4 illustrates the display screen of the operating microscope ofFIG. 1, displaying an image representing the different rates at whichthe fluorescent light intensity changes over time in the blood vesselregion shown in FIG. 2.

FIG. 5 illustrates the display screen of the operating microscope ofFIG. 1, displaying the local changes over time in the fluorescent lightintensity at selected points in the blood vessel region shown in FIG. 2.

FIG. 6 is an image of the blood vessel region shown in FIG. 2 afterperforming neuro-surgical therapy to repair the aneurysm.

FIG. 7 illustrates the display screen of the operating microscope ofFIG. 1, displaying a comparison of the spatial distribution of a maximumintensity of fluorescent light intensity in the blood vessel regionshown in FIGS. 2 and 6 before and after repair of the aneurysm.

FIG. 8 illustrates the display screen of the operating microscope ofFIG. 1, displaying the comparison of images representing the differentrates at which the fluorescent light intensity changes over time in theblood vessel region shown in FIGS. 2 and 6 before and after repair ofthe aneurysm.

FIG. 9 illustrates the display screen of the operating microscope ofFIG. 1, displaying the comparison of the local changes over time in thefluorescent light intensity at selected points in the blood vesselregion shown in FIGS. 2 and 6 before and after repair of the aneurysm.

DETAILED DESCRIPTION

In general, this disclosure relates to medical systems and methods. Insome embodiments, the medical system includes an operating microscopethat is configured to detect and display certain blood flow patternswithin a blood vessel. Certain methods can, for example, includeintroducing a fluorescent substance (e.g., a fluorescent dye) into theblood vessel, and then using the operating microscope to measure afluorescent light intensity in a particular region of the blood vessel(e.g., in a region of the blood vessel including an aneurysm). Incertain embodiments, the operating microscope records a series of imagesof the blood vessel region, analyzes those images, and then produces asingle image that summarizes blood flow patterns that occurred withinthe blood vessel region over the series of images. As a result, thephysician can assess blood flow within the blood vessel region byanalyzing a single image rather than a series of images. In addition,the physician may observe certain blood flow patterns that would not beeasily detected by simply viewing the series of images recorded by themicroscope.

FIG. 1 is a schematic of an operating microscope 1 that is arranged toexamine a surgical site 2. The surgical site 2, which is shown anddescribed in greater detail below, is a portion of the brain with anartery that includes an aneurysm. The operating microscope 1 can bepositioned adjacent the aneurysm in the brain, as shown in FIG. 1, aftera craniotomy has been performed to expose the aneurysm.

The operating microscope includes a lighting system 10 that illuminatesthe surgical site 2, causing stereoscopic viewing beams 3, 4 to passthough a main lens 5. The viewing beams 3, 4 then pass through opticalzoom systems 6, 7, which include powered actuating drives 8, 9 that canbe used to adjust the magnification of the viewing beams 3, 4. Theviewing beams 3, 4 then pass through aperture/filter disks 61, 62 thatcan be used to adjust the amount of light that passes therethrough.After passing through the aperture/filter disks 61, 62, the viewingbeams 3, 4 are directed to eyepieces 28, 29 through which the surgeoncan view the surgical site 2. The viewing beam 4 is also directed bybeam dividers 40 and 43 to a fluorescent camera 41 and by a beam divider40 to a camera 42.

Prior to reaching the camera 41, the divided viewing beam 4 passesthrough a filter 44 transparent to fluorescent light. The filter 44 can,for example, be designed to permit fluorescent light to passtherethrough while blocking other forms of light. The camera 41 detectsthe fluorescent light emitted from the surgical site 2, which isdelivered to the camera 41 in the viewing beam 4, and records images ofthe surgical site 2 based on the detected fluorescent light pattern. Thecamera 41 is adapted to record both continuous video of the surgicalsite 2 and periodic images of the surgical site 2. In addition to thecontinuous video, for example, the camera 41 can record an image (e.g.,a half image) of the surgical site 2 every 120 ms. As described ingreater detail below, fluorescent light can be emitted from the surgicalsite 2 by injecting a fluorescent dye into the surgical site and thencontacting the fluorescent dye with light having a wavelength thatcauses the fluorescent dye to fluoresce. This technique permits thesurgeon to view blood flowing through vessels within the surgical site 2rather than simply the outside of vessels and other matter at thesurgical site 2. The camera 41 can transmit a signal or signalscontaining a continuous video and a series of discrete images of thesurgical site 2 to a signal processing and analysis unit 50. Thecontinuous video can be transmitted from the signal processing andanalysis unit 50 to the touch screen 52 were it is displayed for thesurgeon. In addition, the signal processing and analysis unit 50 cananalyze the series of images and produce a single image, based on theanalysis of the series of images, that represents certain blood flowpatterns within the surgical site over time. The signal processing andanalysis unit 50 can transmit the produced image in the form of a datasignal to a touch screen 52 of the operating microscope 1 where it canbe displayed for the surgeon to view.

The camera 42 is also connected to the signal processing and analysisunit 50. The camera 42 is adapted to record images of the exterior ofthe surgical site 2 and to transmit those images in the form of a signalto the signal processing and analysis unit 50. The camera 42 can recordcontinuous video of the surgical site 2 and/or a series of separateimages of the surgical site 2. The images of the surgical site 2recorded by the camera 42 can be displayed on the touch screen 52 bytransmitting a signal containing the images from the signal processingand analysis unit 50 to the touch screen 52.

The lighting system 10 of the operating microscope 1 includes a Xenonlamp 11, which, when activated, emits light 12 that passes through afilter disk 22. The filter disk 22 includes multiple different filters23, 24, and 25 that enable the lighting system 10 to illuminate thesurgical site 2 with light having a desired range of wavelengths whileinhibiting (e.g., preventing) light with wavelengths outside the desiredrange from being delivered to the surgical site 2. By rotating thefiltering disk 22, the desired filter can be pivoted into the path ofthe light beam for a desired viewing mode.

The filter 23 is provided for situations in which the surgeon wishes toview the surgical site 2 without fluorescent light. The filter 23 can,for example, be used when the surgeon wishes to view the surgical site 2through the eyepieces 28, 29 and when the user wishes to view imagestaken by the camera 42 on the touch screen 52. Filter 23 is a bandpassfilter, which is transparent for light with a wavelength of 400 nm<λ<700nm in the visible part of the spectrum. Filter 23 helps to reduce (e.g.,prevent) stress on the surgical site due to UV radiation and thermalradiation generated by the lamp 11 in the lighting system.

The filter 24 is designed for viewing of the surgical site 2 withfluorescent light of the fluorescent dye ICG The filter 24 is a bandpassfilter, which is transparent for light with a wavelength of 400 nm<λ<780nm in the visible spectrum. When ICG is exposed to light within thisrange of wavelengths it fluoresces.

The filter 25 is designed for viewing of the surgical site 2 withfluorescent light of the fluorescent dye BL 400. The filter 25 is abandpass filter, which is transparent for light with a wavelength of 400nm<λ<410 nm. When BL 400 is exposed to light within this range ofwavelengths it fluoresces.

A screen aperture 21 with regular/random holes is also provided in thelight path of the lighting system 10 for the continuous adjustment ofthe flow of light through the lighting system 10. After passing throughthe screen aperture 21, the light passes through a lens 13 and is thendirected through a light guide 14. An aperture 16 with an adjustableopening is located at the exit 15 of the light guide 14. Light thatpasses through the aperture 16 is routed via luminous field optics 17 tothe surgical site 2. By opening or closing the aperture 16, the amountof light delivered to the luminous field optics 17 can be increased ordecreased. The luminous field optics 17 include an adjustable lenssystem 18 that can be used to adjust the size of a luminous field 90 atthe surgical site 2. An actuator 19 is connected to the lens system 18and can be used to adjust the lens system 18. By adjusting the lenssystem 18, the flow of light from the lighting system 10 to the surgicalsite 2 can be varied and focused based on desired parameters. Thus, theillumination strength in the luminous field 90 can be adjusted asdesired.

A control unit 20 is connected to the lamp 11 and can be used to controlthe flow of light emitted by the lamp 11. The control unit 20 is alsoconnected to an actuator 73 that is coupled to the filter disk 22 suchthat the control unit 20 can control which of the filters 23, 24, 25 ispositioned in the beam of light emitted from the lamp 11.

The powered actuating drives 8, 9 of the zoom system can be connected tothe lens system 18 via the actuator 19 such that when the zoom settingof the operating microscope 1 is changed, the size of the illuminatedfield 90 automatically adjusts to the size of the viewing field.

The aperture/filter disks 61, 62 can be positioned to adjust the amountof light that reaches the eyepieces 28, 29 and the cameras 41, 42.Located inside the aperture/filter disks 61, 62 are apertures 65, 66with different size openings and filters 67, 68 with differenttransmission characteristics. When the aperture 65 is positioned insidethe viewing paths, the operating microscope generates a relatively faintimage with high definition. Positioning the aperture 66 into the viewingpaths ensures a maximum flow of light to the cameras 41, 42 and to theeyepiece lenses 28, 29. To view the surgical site 2 under fluorescentlight, it is advantageous for the flow of light to the camera 41 to beat a maximum level. Thus, when viewing the surgical site 2 underfluorescent light, the disks 61, 62 are generally positioned so that theviewing beams 3, 4 pass through the apertures 66 of the disks 61, 62.The disks 61, 62 are coupled to adjustable drives 63, 74 that can rotatethe disks to the desired position.

As noted above, the fluorescent camera 41 is connected to the signalprocessing and analysis unit 50, which can produce an image based on aseries of images received from the fluorescent camera 41 and cantransmit that image in the form of a signal to the touch screen 52. Thesignal processing and analysis unit 50 is also connected to a controller70. The controller 70 has a memory 72 in which settings related tooperation of the operating microscope 1 in the fluorescent mode arestored. These settings can include, for example, settings for thecurrent of the lamp 11, settings for the filter disk 22, settings forthe screen aperture 21, settings for the adjustable lens system 18 ofthe illuminated field optics 17, and settings for the position of theaperture/filter disks 61, 62. When an activation switch 71 on thecontroller 70 is pressed, the operating microscope 1 is automaticallyconfigured for the fluorescent operating mode. For this purpose, thecontroller 70 is connected to a control unit 20 of the lamp 11, theactuator of the aperture/filter disk 22, the actuating drive 19 for theadjustable lens system 18, the actuating drives 8, 9 for the zoom system6, 7, and the adjustable drives 63, 64 for the aperture/filter disks 61,62. When the microscopy system controller 70 is activated, thecontroller 70 transmits signals to those devices to automatically setthose devices to the values stored in the memory 72. As a result, thesurgeon need not manually adjust various different components every timethe operating microscope 1 is switched between the fluorescent operatingmode and the standard operating mode.

A method of performing and assessing neuro-surgical repair of a brainaneurysm will now be described. Initially, a craniotomy is performed toexpose the region of the artery in the brain that includes the aneurysm.This region is schematically illustrated as the surgical site 2 inFIG. 1. The operating microscope 100 is then positioned with its mainlens 5 adjacent the surgical site 2 and with its lighting system 10arranged to shine light onto the surgical site 2, as shown in FIG. 1.After positioning the operating microscope as desired, the lightingsystem 10 is activated to shine light with a desired wavelength on theexposed artery to allow the surgeon to view the brain aneurysm in adesired manner. The wavelength of the light to which the surgical site 2is exposed can, as discussed above, be controlled by adjustments to thefilter disk 22 of the lighting system 10. Initially, the surgeon canview the surgical site 2 in a standard mode (i.e., a non-fluorescentmode) such that the surgeon can view the exterior of the artery with theaneurysm. The surgeon can view the surgical site 2 through the eyepieces28, 29 or can view images of the surgical site 2 on the touch screen 52.In this standard mode, for example, the camera 42 can record images ofthe surgical site 2 and transmit those images to the touch screen 52 viathe signal processing and analysis unit 50 for display.

FIG. 2 shows the surgical site 2, as viewed through the operatingmicroscope 100 of FIG. 1 in the standard mode. As shown, the surgicalsite 2 includes an artery 240 with an aneurysm 200 that includes ananeurysm sac 210 with evaginations 220 and 230.

Prior to repairing the aneurysm 200, the surgeon can use the operatingmicroscope 100 in a fluorescent mode to view blood flow patterns withinthe artery 240. As discussed below, these blood flow patterns cansubsequently be compared with blood flow patterns through the artery 240after repairing the aneurysm 200 to allow the surgeon to assess thesuccess of the treatment.

To view blood flow patterns within the artery 240, the switch 71 on thecontroller 70 is activated to place the operating microscope 1 in thefluorescent mode. As a result, the controller 70 transmits signals tothe various devices of the operating microscope 1 to which thecontroller 70 is connected to make any desired adjustments to thosedevices. A fluorescent dye (e.g., ICG) is then intravenously injectedinto the bloodstream in the artery 240 upstream of the aneurysm 200. Thefluorescent dye can, for example, be introduced into the bloodstreamover a period of 0.5 second to several seconds (e.g., 0.5 second to twoseconds). The lighting system 10, which was automatically adjusted bythe controller 70, transmits the light 12 at a wavelength that causesthe fluorescent dye within the artery 240 to fluoresce. As a result,those portions of the artery 240 that are supplied with blood (and thussupplied with the fluorescent dye) will generate fluorescent light. Thefluorescent light emitted from the fluorescent dye within the artery 240passes through the main lens 5 and the zoom system 7 and is directed tothe camera 41 by the beam dividers 40 and 43. A continuous video of thesurgical site 2 is recorded by the camera 41 and transmitted to thesignal processing and analysis unit 50. The continuous video of thesurgical site 2 can be immediately displayed on the touch screen 52 forthe surgeon to view in real time. While recording the continuous video,a series of fluorescent images of the surgical site 2 are also recordedby the camera 41 and transmitted in the form of signals from the camera41 to the signal processing and analysis unit 50 where they are stored.The signal processing and analysis unit 50 analyzes the images andproduces a single image that summarizes the flow pattern within theartery 240. A signal containing the image produced by the signalprocessing and analysis unit is then transmitted to the touch screen 52where the image is displayed.

The type of image that is produced within the signal processing andanalysis unit 50 and then displayed on the touch screen 52 can be chosenby the surgeon by selecting a desired button on the touch screen 52. Forexample, the user can select a button that causes the signal processingand analysis unit 50 to produce an image that shows a spatialdistribution of the maximum intensity of fluorescent light across thesurgical site 2, a button that causes the signal processing and analysisunit 50 to produce a spatial image of the change over time of thefluorescent light intensity across the surgical site 2, and/or a buttonthat causes the signal processing and analysis unit 50 to produce animage of the intensity of fluorescent light over time at selectedlocations of the surgical site 2.

FIG. 3 is a screen shot of the touch screen 52. As shown, a Map tab 403has been selected and the surgeon has opted to view the maximumintensity of the fluorescent light in the imaged region by selecting aMaximum Intensity button 404. As a result of these selections, thesignal analysis and processing unit 50 analyzes each point (e.g., eachpixel) on the series of images transmitted to it by the fluorescentcamera 41 and identifies the maximum fluorescent intensity that occurredat each point over the series of images. The signal analysis andprocessing unit 50 then produces an image that depicts the surgical site2 based on the maximum fluorescent intensity that was observed at eachpoint in the surgical site 2. That image is then transmitted in the formof a signal to the touch screen 52 where it is displayed in a displayfield 401. As indicated on the brightness scale 405, the highestfluorescent intensity recorded at the target site is shown as beingbrightest, the lowest fluorescent intensity recorded at the target siteis shown as being darkest, and intermediate intensities are shown ashaving varying levels of brightness therebetween depending on theirintensities.

Still referring to FIG. 3, the aneurysm 402 at the surgical site isshown as having about the highest fluorescent light intensity in thesurgical site. This is because the concentration of the fluorescent dyeis greatest in those regions of the surgical site through whichrelatively large amounts of blood flow. In contrast to thebrightly-displayed aneurysm 402, tissue regions that surround the arteryand receive less blood are shown as being darker. Thus, by looking atthis image, the surgeon can quickly determine the local densitydistribution of blood at the surgical site, which can help the surgeonto determine the severity of the aneurysm and the supply of blood to theaneurysm.

A motion compensation technique can be applied to the captured images bythe signal processing and analysis unit 50 before determining themaximum intensities. Such a technique can improve the sharpness andreduce blurriness of the images. The motion compensation uses an edgedetection process to generate edge images of the individual images inorder to correlate them and to thus determine the alignment vector. Thisprocedure allows the correlation of the edge image of an individualimage with a respective reference image. The reference image is thendeveloped further by being complemented by the “misaligned” actual edgeimage. The signal processing and analysis unit 50 can, for example,analyze a region of the image displaying the edge of the artery 400 andsurrounding tissue. The demarcation between the edge of the artery 400and the surrounding tissue, which will show up as a much different lightpattern in the images, can be used as a reference point for subsequentimages. In particular, the signal processing and analysis unit 50 canadjust subsequent images to ensure that the demarcation between theartery 400 and the surrounding tissue in those images is positioned atthe same location as it is in the reference image. This will help toensure that specific features of the surgical site show up at the samelocation on each of the images analyzed by the signal analysis andprocessing unit 50. As a result, the analysis performed by the signalprocessing and analysis unit 50 will be accurate even if the operatingmicroscope 1 experiences some movement during the procedure.

Before determining the maximum intensities, a brightness correction isalso applied to the individual images. In order to make this possible,the information required for the brightness correction is recorded andstored as meta data together with the captured images. Any of variousknow gain control techniques can be used to correct or adjust thebrightness of the various images.

FIG. 4 is another screen shot of the touch screen 52. As shown, the Maptab 403 has been selected and the surgeon has opted to view the rate atwhich the various points in the imaged region reach a thresholdfluorescent light intensity by selecting the Delay button 504. As aresult of these selections, the signal analysis and processing unit 50analyzes each point (e.g., each pixel) on the series of imagestransmitted to it by the fluorescent camera 41 and determines the periodof time that it took for each of those points to reach the thresholdfluorescent light intensity. The operating microscope 1 then displays onthe touch screen 52 a false color image that represents the amount oftime that it took the various points of the surgical site to reach thethreshold fluorescent light intensity.

To determine the change in the fluorescent light intensity over time,the signal processing and analysis unit 50 compares the fluorescentintensity experienced at each point on the series of images to thethreshold intensity value. The threshold intensity value can, forexample, be 50 percent of the maximum fluorescent intensity recorded atthe particular point being analyzed. Any of various other thresholdintensity values can alternatively be used. In certain cases, forexample, the threshold intensity value is 20 percent of the maximumfluorescent light intensity. In order to determine the threshold valuefor each point or area to be viewed, a brightness graph of the signalcan be produced within the signal processing and analysis unit 50 andthen the signal processing and analysis unit 50 can determine at whichpoint in time the threshold intensity value was reached. The signaltransmitted from the camera 41 to the signal processing and analysisunit 50 can, for example, include information related to the time thateach image was recorded in addition to the information related to thefluorescent intensity of the image to allow the signal processing andanalysis unit 50 to compare the points in time at which each of thevarious points reached the threshold intensity value.

Still referring to FIG. 4, the relative time that it takes for eachpoint to reach the threshold intensity value is displayed as a falsecolor image in display field 501. As indicated on the brightness scale505, the point or points that experienced the shortest time period toreach the threshold intensity value is/are shown in red, the point orpoints that experienced the longest time period to reach the thresholdintensity value is/are shown in blue, and the point or points thatexperienced intermediate time periods to reach the threshold intensityare shown as a combination of blue and red. Thus, regions of thesurgical site that have good blood flow and thus are supplied with bloodearly will typically be shown nearer the red end of the color scalewhile regions of the surgical site that have poor blood flow and thusare supplied with blood late will typically be shown nearer the blue endof the color scale. The artery supplying the blood, which includes theunrepaired aneurysm 502, is shown as being nearer the red end of thecolor scale, thereby indicating that blood is flowing into the aneurysm502 via this vessel. In contrast, tissue regions surrounding the artery(e.g., abducent vessels in tissue regions surrounding the artery) areshown as being nearer the blue end of the color scale, therebyindicating later blood flow in those regions. This image can help thesurgeon to determine the severity of the aneurysm and the blood supplyto the aneurysm.

A high-resolution display of image information is possible by subjectingthe individual images to motion compensation and brightness correctiontechniques of the type described above with regard to FIG. 3.

FIG. 5 is another screen shot of the touch screen 52. As shown, aDiagram tab 611 has been selected, and, as indicated in display field602, the surgeon has selected regions 603, 604, 605, 606 of the imagedsurgical site in order to view the intensity of the fluorescent lightover time at those regions of the imaged surgical site. Display field602 displays the spatial distribution of the fluorescent light intensityat the surgical site and includes boxes over various regions 603, 604,605, 606 of that image, which indicate regions of the site that thesurgeon has chosen to view. The surgeon can select the sites to beviewed by simply touching the portion of the screen that displays theregion of the image in which the surgeon is interested. As a result ofthe selections made by the surgeon, the signal analysis and processingunit 50 analyzes each selected region 603, 604, 605, 606 on the seriesof images transmitted to it by the fluorescent camera 41 and charts themean fluorescent light intensity at those regions over time. Thisinformation is then transmitted to the touch screen 52 where it isdisplayed in a display field 601 as intensity characteristics 607, 608,609 610.

The surgeon can choose which of the regions 603, 604, 605, 606 to viewgraphs of by selecting buttons 612, 613, 614, 615 on the touch screen52. While graphs are displayed in the display field 601 for only fourselected regions, the surgeon can select up to eight regions and canelect to view graphs of any number of those regions at a given time beselecting or deselecting the buttons on the touch screen that correspondto those regions.

Regions 603, 604, 605, and 606 selected by the surgeon on the displayfield 602 are regions for analysis. They are stored as individual imagesfrom the sequence captured by the camera 41 in the operating microscope1. In doing so, position-dependent values are determined, where theposition to be analyzed, a starting pixel, is selected and an analysisregion is defined at this position. The determination of the size and/orform of the analysis region occurs automatically and dependently on thecontent of the image. The maximum size of the analysis region ispredetermined. For example, the maximum diameter of the analysis regioncan be between 3% and 5% of the side length of the respective image. Themaximum number of pixels in an analysis region can also be predefined.The size of an analysis region is based on the edge of the image to beanalyzed. The shape of the analysis region follows, at least in someareas, the shape of the image content. The pixels of the analysis regionare determined by comparing their value to the value of the start-uppixel. Pixels for the analysis region are selected when the differencebetween their values and the value of the starting pixel lies within thepositional deviation of the pixel values of a defined region. In thisrespect, the analysis region is a cohesive area, wherein the analysisregion is adjusted to every individual image of the image sequence to beanalyzed. Before the analyzing regions are defined, a motioncompensation is applied to the individual images.

The analysis of the image data in the selected area region on thedisplay field 602 on the display screen is started only after thesurgeon has confirmed the selected position. For this purpose, thesurgeon must touch the desired area on the display field 602. Theselected position is located on the display in the central area of theenlarged section of the image data. The side length of the central areais 50% of the side length of the magnified section. The side length ofthe central region may also be 25% of the magnified section. In theboundary area of the image data, the central region is moved in thedirection of the boundary of the magnified section. In doing so, theimage data are analyzed such that the position selected by the surgeonis corrected before it is confirmed. However, an automatic confirmationafter the correction is also possible. The surgeon can confirm theposition by touching a control field on the display screen. In doing so,the image data can be corrected multiple times. It is, however,advantageous for the position of the image data to be correctedautomatically. For this purpose the system, using an object detectionroutine, the position is moved to the nearest object. The magnifiedsection is then enlarged in several steps.

The time characteristic of the intensity averaged across a selected areavisualized on the display field 601 quantifies the blood flow in theselected area sections. This can, for example, help the surgeon todetermine the severity of the aneurysm.

After studying the blood flow patterns through the surgical site byreviewing the various images displayed by the touch screen 52 (as shownin FIGS. 3-5) the surgeon can repair the aneurysm with one or moreclips.

FIG. 6 shows the surgical site 2, as viewed through operating microscope1, after placing a clip 320 at the aneurysm sac 210 and the evagination220, and a clip 330 at the evagination 230 of the aneurysm sac 210.

It is beneficial for the surgeon to verify the success of the aneurysmrepair during the surgery. The surgeon can, for example, verify thesuccess of the aneurysm surgery by determining (1) if the aneurysm iseliminated or greatly reduced by the clips 320, 330, (2) if arterialblood continues to flow into the aneurysm sac 210 and its evaginations220, 230 despite the applied clips 320, 330, and/or (3) if the bloodflow through the artery is constricted or even interrupted by the clips320, 330. In order to make these determinations, the techniquesdescribed above with respect to FIGS. 3-5 can be repeated after theclips 320, 330 have been positioned about the aneurysm. This allows thesurgeon to view the blood flow patterns at the surgical site afterrepair of the aneurysm, and thus assess the efficacy of the treatment.

The operating microscope 1 also offers the surgeon the option tosimultaneously display (on the touch screen 52) images related to bloodflow patterns at the surgical site 2 prior to repairing the aneurysm andimages related to blood flow patterns at the surgical site 2 afterrepairing the aneurysm. This enables the surgeon to assess the successof the aneurysm surgery based on the displayed information on a singledisplay screen.

FIG. 7 is a screen shot of the touch screen 52 with a display field 701showing the spatial distribution of the fluorescent light intensity atthe surgical site before the aneurysm was repaired and a display field702 showing the spatial distribution of the fluorescent light intensityat the surgical site after the aneurysm was repaired. As shown, thesurgeon has accessed this screen by pressing a Compare tab 703 and hasopted to view the maximum intensity at the surgical site by pressing aMaximum Intensity button 704. The spatial distribution of thefluorescent light intensity is obtained and displayed using theprocedure described above with respect to FIG. 3. In particular, theprocedure described with respect to FIG. 3 is repeated after repairingthe aneurysm such that the operating microscope 1 collects sufficientdata to display the spatial distribution of the fluorescent lightintensity at the surgical site before and after the aneurysm repair.From the touch screen 52 shown in FIG. 7, the surgeon can quicklydetermine that due to the clips, the area 710 of the surgical field,which originally contained the aneurysm, no longer receives blood. Thisindicates that the aneurysm was successfully treated with the aneurysmsurgery.

FIG. 8 is a screen shot of the touch screen 52 with a display field 801showing the spatial distribution of the rate at which the fluorescentlight intensity at the various different points of the surgical sitereached a threshold intensity value before the aneurysm was repaired andwith a display field 802 showing the spatial distribution of the rate atwhich the fluorescent light intensity at the various different points ofthe surgical site reached the threshold intensity value after theaneurysm was repaired. As shown, the surgeon has accessed this screen bypressing the Compare tab 703 and has opted to view the time required toreach the threshold intensity value at each of the various points bypressing a Delay button 804. The spatial distribution of the timerequired for the various points to reach the threshold intensity valueis obtained with the procedure described with respect to FIG. 4. Inparticular, the procedure described with respect to FIG. 4 is repeatedafter repairing the aneurysm such that the operating microscope 1collects sufficient data to display the spatial distribution of the timerequired for each of the points at the surgical site to reach thethreshold intensity value before and after the aneurysm repair. From thedisplay screen shown in FIG. 8 the surgeon can determine that due to theapplied clips blood is not allowed to flow into area 810 of the surgicalfield, not even with a delay. Again, this allows the surgeon to concludethat the aneurysm surgery in this area was successful.

FIG. 9 is a screen shot of the touch screen 52 with a display field 901showing graphs 902, 903, 904, 905, 906, and 907 that represent the localtime characteristic of the fluorescent light intensity at tissue regions908, 909, 910, 911, 912 and 913 of the surgical site, which is shown ina display field 914, before repair of the aneurysm. A display field 915similarly shows graphs 916, 917, 918, 919, 920, and 921 that representthe local time characteristic of the fluorescent light intensity attissue regions 908, 909, 910, 911, 912 and 913 of the surgical siteafter repair of the aneurysm. As shown, the surgeon has accessed thisscreen by pressing the Compare tab 703 and has opted to view graphs ofthe intensity at the selected regions of the surgical site by pressing aDiagram button 921. Graphs 902-907 are obtained with the proceduredescribed above with respect to FIG. 5. In particular, the proceduredescribed with respect to FIG. 5 is repeated after repairing theaneurysm such that the operating microscope 1 collects sufficient datato display the local time characteristic of the fluorescent lightintensity at the selected tissue regions of the surgical site before andafter the aneurysm repair. The information provided in display fields901 and 915 allows the surgeon to assess the success of the aneurysmsurgery. In particular, the comparison of the characteristics of thefluorescent light intensity graphs over time allows the surgeon todetermine the local change in blood flow at the surgical site. As aresult, it is possible for the surgeon to detect any undesired stenosis,i.e., constrictions of the blood vessels, caused by the application ofthe clips to the aneurysm. Conventional visualization procedures forstructures at a surgical site are typically not able to detect this typeof stenosis.

The procedures described herein can be performed especiallyadvantageously with an operating microscope of the type shown in FIG. 1,which allows the surgeon to view the surgical site with the operatingmicroscope throughout the entire aneurysm surgery without having to movethe microscope away from the surgical site in order to make room forother diagnostic devices.

While certain embodiments have been described, other embodiments arepossible.

In some embodiments, the explained procedure for the treatment of ananeurysm is performed several times in a row. If, for example, in thefirst attempt the surgeon was unable to clamp off the aneurysm with theclip or if the patient's blood flow is negatively affected, then thesurgeon can remove the clip, re-apply it, and check the effect based onthe explained procedure.

While the maximum fluorescent light intensity has been described asbeing shown as a particular brightness, the maximum fluorescent lightintensity can alternatively or additionally be displayed as a color. Thedifferent maximum fluorescent intensities at the surgical site can, forexample, be displayed as different colors along a color scale.

Similarly, while the amount of time for the various different points atthe surgical site to reach the predetermine threshold fluorescent lightintensity value has been described as being shown as a particular color,this can alternatively or additionally be displayed as a brightness. Thedifferent times required to reach the threshold intensity value can, forexample, be displayed as different levels of brightness along abrightness scale.

While color scales described herein for displaying different blood flowpatterns range from red to blue, any of various other color scales canalternatively be used. In certain embodiments, for example, the colorscale progresses from red to yellow to green to blue. For example, thosepoints that required the shortest periods of time to reach the thresholdintensity value can be displayed as blue, those points that required thelongest periods of time to reach the threshold intensity value can bedisplayed as red, and those points that required intermediary periods oftime to reach the threshold intensity value can be displayed as variousshades of yellow or green.

While certain methods described above include introducing ICG into theblood vessel of the patient, any of various other fluorescent dyes canalternatively or additionally be used. In some embodiments, for example,BL is used. In such embodiments, the operating microscope 1 is adjustedto allow for the detection of the fluorescent light emitted by the BL.The filter disk 22 of the lighting system 10 can, for example, berotated so that the bandpass filter 25 is positioned in the beam oflight 12 emitted by the lamp 11.

While certain methods described above include performing neuro-surgicaltherapy to repair a brain aneurysm, the methods can alternatively oradditionally include the performance of other techniques, such asendovascular therapy, to repair the brain aneurysm.

While certain methods described above relate to treating and assessingtreatment of a brain aneurysm, the methods can alternatively be used fortreating and assessing treatment of aneurysms in various other parts ofthe body.

Similarly, while certain methods described above relate to treating andassessing treatment of aneurysms, the methods can alternatively oradditionally be used to treat and assess treatment of various othermedical conditions. For example, the methods described herein can beused for bypass surgeries, stent implantations, arterial venousmalformation (AVM) therapies, determining arterial venous transmissiontime, or any of various other medical treatments in which the flow ofblood may be affected.

While certain methods described above relate to assessing fluid flowpatterns in a blood vessel, the methods can alternatively oradditionally be used to assess fluid flow through other types of bodyvessels. Examples of other types of body vessels in which the methodscan be used are urethras and bowels.

While certain devices of the operating microscope 1 have been describedas including actuators that automatically adjust those devices, theoperating microscope 1 can alternatively or additionally be configuredso that those devices can be manually adjusted.

While the operating microscope 1 has been described as including a Xenonlamp, any of various other light sources can alternatively oradditionally be used. Examples of other light sources include halogenlamps, LED lamps, and mercury lamps.

While operating microscope 1 has been described as including a touchscreen, any of various other types of monitors, including monitors withhard keypads, can be used.

Other embodiments are within the scope of the following claims.

1.-32. (canceled)
 33. A method, comprising: recording a first pluralityof images of a region of a blood vessel; analyzing the first pluralityof recorded images to determine a maximum fluorescent light intensity atmultiple points on each of the first plurality of recorded images; anddisplaying a first image that represents the maximum fluorescent lightintensity at each of the multiple points on each of the first pluralityof recorded images.
 34. The method of claim 33, wherein the regioncomprises multiple blood vessels. 35.-48. (canceled)
 49. The method ofclaim 33, further comprising, after displaying the first image:recording a second plurality of images of the region of the bloodvessel; analyzing the second plurality of recorded images to determine amaximum fluorescent light intensity at multiple points on each of thesecond plurality of recorded images; and displaying a second image thatrepresents the maximum fluorescent light intensity at each of themultiple points on each of the second plurality of recorded images. 50.The method of claim 49, further comprising simultaneously displaying thefirst and second images.
 51. The method of claim 50, wherein the firstand second images are displayed in a side-by-side fashion.
 52. Themethod of claim 51, further comprising repairing an aneurysm at theregion of the blood vessel.
 53. The method of claim 52, furthercomprising: before recording the first plurality of images, injecting afluorescent dye into the blood vessel; after injecting the fluorescentdye into the blood vessel, applying a clip to the aneurysm to clamp offthe aneurysm; and after applying the clip to the aneurysm, capturing thesecond set of images.
 54. The method of claim 49, further comprisingrepairing an aneurysm at the region of the blood vessel.
 55. The methodof claim 54, wherein the first image is displayed before repairing theaneurysm at the region of the blood vessel, and the second image isdisplayed after repairing the aneurysm at the region of the bloodvessel.
 56. The method of claim 55, further comprising: before recordingthe first plurality of images, injecting a fluorescent dye into theblood vessel; after injecting the fluorescent dye into the blood vessel,applying a clip to the aneurysm to clamp off the aneurysm; and afterapplying the clip to the aneurysm, capturing the second set of images.57. The method of claim 54, further comprising: before recording thefirst plurality of images, injecting a fluorescent dye into the bloodvessel; after injecting the fluorescent dye into the blood vessel,applying a clip to the aneurysm to clamp off the aneurysm; and afterapplying the clip to the aneurysm, capturing the second set of images.58. The method of claim 34, further comprising, after displaying thefirst image: recording a second plurality of images of a region of ablood vessels; analyzing the second plurality of recorded images todetermine a fluorescent light intensity at each of multiple points oneach of the second plurality of recorded images; and displaying a secondimage that represents the fluorescent light intensity for each of themultiple points over a period of time on each of the second plurality ofimages.
 59. The method of claim 58, further comprising simultaneouslydisplaying the first and second images.
 60. The method of claim 59,wherein the first and second images are displayed in a side-by-sidefashion.
 61. The method of claim 60, further comprising repairing ananeurysm at the region of the blood vessels.
 62. The method of claim 61,further comprising: before recording the first plurality of images,injecting a fluorescent dye into the blood vessel; after injecting thefluorescent dye into the blood vessel, applying a clip to the aneurysmto clamp off the aneurysm; and after applying the clip to the aneurysm,capturing the second set of images.
 63. The method of claim 58, furthercomprising repairing an aneurysm at the region of the blood vessel. 64.The method of claim 64, wherein the first image is displayed beforerepairing the aneurysm at the region of the blood vessel, and the secondimage is displayed after repairing the aneurysm at the region of theblood vessel.
 65. The method of claim 65, further comprising: beforerecording the first plurality of images, injecting a fluorescent dyeinto the blood vessel; after injecting the fluorescent dye into theblood vessel, applying a clip to the aneurysm to clamp off the aneurysm;and after applying the clip to the aneurysm, capturing the second set ofimages.
 66. The method of claim 63, further comprising: before recordingthe first plurality of images, injecting a fluorescent dye into theblood vessel; after displaying the first image, applying a clip to theaneurysm to clamp off the aneurysm; and after applying the clip to theaneurysm, capturing the second set of images.